Trochomorpha haptoderma Vermeulen, Liew & Schilthuizen

Vermeulen, Jaap J., Liew, Thor-Seng & Schilthuizen, Menno, 2015, Additions to the knowledge of the land snails of Sabah (Malaysia, Borneo), including 48 new species, ZooKeys 531, pp. 1-139 : 98

Taxon classification Animalia Stylommatophora Trochomorphidae

Trochomorpha haptoderma Vermeulen, Liew & Schilthuizen sp. n. Figure 80

Holotype.

Malaysia, Sabah, West Coast Province, Kinabalu N.P., near Summit trail (leg. T.S. Liew et al., BOR/MOL 6046).

Examined material from Sabah.

West Coast Province. Kinabalu N.P., Summit trail between 2560 and 3330 m (leg. M. Schilthuizen & P. Koomen, BOR/MOL 1205; leg. T. Narainan, BOR/MOL 2673, BOR/MOL 2690, BOR/MOL 2880; leg. T.S. Liew, BOR/MOL 3995; leg. M. Schilthuizen, BOR/MOL 2997); Kotal’s route between 2376 and 3112 m (leg. T.S. Liew, BOR/MOL 3987; (leg. T.S. Liew & Jasilin, BOR/MOL 3988, BOR/MOL 4106, BOR/MOL 3989, BOR/MOL 3990, BOR/MOL 3991); Kiau-Spurs trail between 3024 and 3088 m (leg. T.S. Liew, J. Lapidin & Safrie, BOR/MOL 3994, BOR/MOL 3997, BOR/MOL 3992); Sayap-Nunuhon trail between 2320 and 2944 m (leg. T.S. Liew, Dominik, J. Lapidin & Jasilin, BOR/MOL 4405, BOR/MOL 3993); Mesilau trail between 1948 and 2528 m (leg. T.S. Liew, BOR/MOL 3996); Monggis-Tambuyukon trail at 2360 m (leg. T.S. Liew, BOR/MOL 4108).

Description.

Shell medium-sized, rather thin, about opaque, yellowish brown, moderately low-conical with somewhat convex sides; apex slightly protruding. Surface with a silky luster above the periphery, shiny below. Whorls: Apical whorls convex, outer slightly convex; suture moderately impressed, coinciding with the periphery; last whorl angular, hardly compressed at the periphery, rounded below the periphery. Protoconch 1 7/8-2 1/4 whorls, with dense radial riblets except at the apex, and a spiral striation cutting into the radial riblets towards the teleoconch; transition to teleoconch sculpture gradual. Teleoconch. Radial sculpture: above the periphery rather densely placed, more or less regularly spaced riblets; below the periphery growth lines only. Spiral sculpture: last whorl with a peripheral thread; start of fifth whorl with 11-14 spiral threads: 2-8 rather distinct, rather low and wide threads but with a narrow crest, which are highest or form nodes over the radial sculpture, and 5-12 similar but less conspicuous threads interspersed; no spiral sculpture below the periphery. Umbilicus closed. Peristome slightly thickened and slightly reflexed, more distinctly so on the columellar side. Dimensions: Height 7.4-10.0 mm; width 14.0-17.0 mm; h/w 0.53-0.59; diameters of the first 4 whorls 1.7-1.9 mm, 3.0-3.3 mm, 5.0-5.5 mm, 7.5-8.2 mm respectively; number of whorls 5 1/2-6 1/8, height aperture 5.0-6.0 mm; width aperture 6.5-8.5 mm.

Habitat in Sabah and distribution.

Montane and sub-alpine forest on sandstone bedrock, 1900-3300 m alt. Sabah: Mount Kinabalu only. Endemic to Sabah.

Cross diagnosis.

Consistently larger than Trochomorpha rhysa , and less densely coiled. The sculpture above the periphery is coarser, particularly the radial riblets on the protoconch, as well as the spiral threads on the teleoconch. The latter are also less regularly spaced, and of more unequal strength, with much more inconspicuous threads interspersed in between the distinct ones.

Etymology.

The name refers to the knotted shell surface [hapto (Gr.) = to knot; derma (Gr.) = skin].